It was one of those dreams that felt so real, I thought it had actually happened, but then I woke up and realized it was a dream

Both are creatures in Cherokee Indian mythology.
The Uktena was a gigantic, antlered serpent with a gem in its forehead. It could also spit corrosive venom which, if it hits your skin, will cause a tiny snake to grow from the spot the venom touched.
According to legend, a medicine man was captured by the Cherokee once. The medicine man said that if the Cherokee let him go, he would get the Uktena's gem. They let him go, and he eventually found the Uktena. He made a barrier of fire to protect himself from the venom, then shot at the seventh spot back from the Uktena's head (where its heart is) and killed it.

The Tlanuwa was described as a huge hawk or falcon. It would supposedly swoop down on villages to eat dogs and even small children. So one day a warrior decided to find the nest of the Tlanuwa. It found the nest, destroyed the eggs, and the Tlanuwa was so distraught that it flew away and was never seen again.
Also, the Tlanuwas and the Uktenas are natural enemies. Uktenas would often eat Tlanuwa eggs that fell from the nest, which understandably made the parent Tlanuwas angry.